NASA flight controllers waved off two Florida landing opportunities earlier in the day, because of rain and thunderstorms near the Kennedy Space Center. So, the space agency diverted Discovery and its seven astronauts to the shuttle's backup landing site at Edwards Air Force Base.

Discovery's return to terra firma was originally scheduled for Thursday, but rain and wind also thwarted NASA's earlier attempts.

Tonight's first landing opportunity at Edwards would begin de-orbit at 7:47 p.m. EDT (11:47 p.m. GMT) with a landing 56 minutes later. The second opportunity has a de-orbit time at 9:23 p.m. EDT (1:23 a.m. GMT) with a landing 65 minutes later.

NASA doesn't fancy California landing because the shuttle's cross-country ferry trip back to Florida takes more than a week and costs about $1.7 million.

Discovery's mission STS-128 returns from a journey to restock the International Space Station with supplies and science equipment for the station's crew of six. The shuttle also returns with specialist Tim Kopra, who arrived aboard Endeavour back in July. He was replaced by flight engineer Nicole Stott. ®